Employee Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2014

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock-Based Compensation Expense

	Stock-Based Compensation Expense (in thousands)
	Three-month period ended				Nine-month period ended
	September 30, 2014		September 30, 2013		September 30, 2014		September 30, 2013
Research and development	$	1,113	$	468	$	3,225	$	1,145
Sales, general and administrative		1,290		540		4,109		1,467
Total stock-based compensation expense	$	2,403	$	1,008	$	7,334	$	2,612

Stock Option Activity

Stock Option Activity
	Number of Shares			Weighted Average Exercise Price per Share
Options Outstanding December 31, 2013	5,160,086		$	3.45
Granted	709,025		$	15.78
Cancelled	(13,678	)	$	13.06
Exercised	(255,000	)	$	2.86
Expired	—			—
Options Outstanding September 30, 2014	5,600,433		$	5.01

Stock Option Supplemental Information

Stock Option Supplemental Information
		Options Outstanding		Options Exercisable
Number of options		5,600,433		1,756,885
Weighted average remaining contractual term (in years)		8.15		7.72
Weighted average exercise price	$	5.01	$	2.26
Weighted average fair value	$	3.85	$	1.52
Aggregate intrinsic value (in thousands)	$	92,000	$	34,000